Oreocharis fulvovillosa M. Q. Han, H. Jiang & Y. Wang sp. nov.

Fig. 1

Diagnosis.

The new species is most similar to Oreocharis bullata, sharing yellow corollas and bullate leaf blades, but differs in having crenulate leaf margins (vs. double dentate), a slender corolla tube ca. 1 cm long (vs. tubular, ca. 2.7 cm long), and shorter capsules 1–1.9 cm long (vs. 3.0– 4.2 cm long). It is also similar to Oreocharis fulva in corolla shape and colour but differs in having bullate leaf blades (vs. not bullate) and crenulate margins (vs. serrate to crenate).

Type.

China • Yunnan Province: Dehong Dai and Jingpo Autonomous Prefecture, Mang city, 1950 m, a. s. l, on the surface of moist cliffs, 24°14'N, 98°21'E, 27 August 2025, Mengqi Han & Yang Wang HMQ 2486 (holotype: KUN [KUN 1729596]; isotypes: CDIB [CDBI 0309749], PE).

Description.

Perennial herb with very short rhizomatous stems and crowded roots. Leaves basal, arrangement spiral, 7 to 12 per plant; petioles 2–5 cm long, densely covered with long fulvous hairs; leaf blades ovate to broadly ovate, 2.5–5.5 × 3–6 cm, papery when dried, shallowly heart-shaped at bases, margins crenulate, soft hairs closely adhered to both sides, adaxial bullate; lateral veins ca. 4–6 on either side of midrib, abaxially conspicuous. Pair-flowered cymes 2–6, axillary, 2–6 - flowered; peduncles 3–5 cm long, densely pilose; bracts two, opposite, lanceolate, ca. 2 mm long, sparsely pilose; pedicels ca. 2.5 cm, sparsely pilose. Calyx 5 - lobed nearly to base, lobes lanceolate, nearly equal, ca. 4 mm long, outside sparsely glandular-pilose, glabrous inside. Corolla yellow, bilabiate, ca. 2 cm long; corolla tube tubular, slender, ca. 1 cm long, outside covered with glandular hairs (surface pustulose at base of hairs), glabrous inside; limb 2 - lipped, both surfaces sparsely covered with glandular hairs, adaxial lip ca. 7 mm, 2 - lobed to middle; abaxial lip ca. 11 mm, three-lobed to approximately one-third from the base, lobes almost equal, oblong, 6–7 × 8–9 mm. Stamens four, included; filaments white, glabrous, curved backwards near apex, adaxial ca. 12 mm long, adnate to corolla tube ca. 4 mm from base, abaxial ca. 15 mm long, adnate to corolla tube ca. 4 mm from base; anthers ca. 0.5 mm long, coherent in two pairs, elliptic, basifixed, dehiscing longitudinally, oriented upwards due to the backward curvature of the filaments; staminode one, white, glabrous, adnate to the corolla tube ca. 1.5 mm above the base, ca. 1.5 mm long. Pistil included, 8–9 mm long when stigma mature, glabrous; ovary yellowish green when unpollinated, becoming yellowish brown after fertilization, grooved, ca. 6 mm long when stigma mature, 1 - loculed, placentas two, parietal, bifid, intrusive, adaxial lobes smaller; style faint yellow, 4–5 mm when stigma mature; disc ring-like with slightly undulated margin, 2–3 mm high; stigma 2 - lobed, lobes ca. 1 mm long. Capsules straight relative to pedicel, brown, oblong, 10–19 × 3 mm, valves straight, dehiscing loculicidally, calyx deciduous, not caducous.

Phenology.

The new species has been collected in flower from August to September, and fruiting was observed during field observation in September.

Etymology.

The epithet refers to the fulvous (yellowish) colour of the long, soft hairs on the petioles.

Vernacular name.

Chinese Mandarin: dé hóng zhí bàn jù tái, (德宏直瓣苣苔).

Distribution, habitat, and ecology.

Oreocharis fulvovillosa was observed growing on moist, shady cliffs on a limestone hill, 1950 m a. s. l., in the Dehong Dai and Jingpo Autonomous Prefecture of Yunnan, China.

Conservation status.

Oreocharis fulvovillosa is a rare species with an extremely restricted distribution and a very small population size. It is currently known only from the type locality in an isolated karst area of Mang City, which lies outside any formally protected area. Targeted field surveys were conducted in the surrounding areas within a radius of approximately 1 km, but no additional subpopulations were located.

At present, the species is known from a single location, near the summit of a small limestone hill, where the plants grow on a cliff face of approximately 50 × 50 m. The extent of occurrence (EOO) cannot be meaningfully calculated from a single known location, and the area of occupancy (AOO) is estimated as 4 km 2 based on the IUCN standard 2 × 2 km grid. The total number of mature individuals is estimated to be approximately 70.

Given its extremely limited distribution, single location and small population size, the species is potentially threatened by stochastic events and human disturbance (e. g. habitat degradation or collection). Following the IUCN Red List Categories and Criteria (IUCN 2024), O. fulvovillosa qualifies as Critically Endangered (CR B 1 ab (iii) + B 2 ab (iii); D). This assessment should be regarded as preliminary and subject to revision pending further field surveys in adjacent karst areas.

Additional specimens examined (paratypes).

China • Yunnan, Dehong Dai and Jingpo Autonomous Prefecture, Mang city, 24°14'N, 98°21'E, 1950 m, a. s. l, on the surface of moist cliffs, 5 September 2020, Mengqi Han HMQ 1823 (PE).

Notes.

Oreocharis hekouensis (Y. M. Shui & W. H. Chen) Mich. Möller & A. Weber is included in Table 1 for comparison because it shares a generally similar leaf shape with the new species. However, it can be readily distinguished from O. fulvovillosa by several characters. The new species has bullate leaf blades (vs. not bullate), crenulate margins (vs. crenate) and a much shorter corolla tube ca. 1 cm long (vs. 2.4–3.0 cm long). In addition, the calyx lobes are shorter, ca. 4 mm long (vs. ca. 10 mm long), the stamens are adnate to the corolla tube for 2–2.5 mm (vs. 7–8 mm), and the capsules are 1–1.9 cm long (vs. 2.5–3.8 cm long).